Wireless sensor network (WSN) applications are often deployed under hostile environments. Monitoring sensor nodes carefully, detecting and providing defence against malicious activity in the region is a challenging task. Legitimate sensor nodes may be captured by an adversary to extract important security information regarding shared secrets and cryptographic keys. This type of attack may result in a severe WSN security breach. Using ‘tamper-resistant’ nodes for securing communication in a WSN cannot be considered as a solution against these attacks as it increases the network cost tremendously. Nevertheless, destroying a legitimate node by erasing its memory and destroying its radio service based on a misjudgement may bring severe damage to the WSN. The authors propose the novel sensor node capture attack detection and defence (SCADD) protocol. SCADD provides a cost-effective solution against the node compromise and capture attacks in WSNs, enhancing the overall WSN security for security-sensitive applications. This protocol consists of two building blocks: node attack detection block and defence advocating measure block. The former provides strategic-based attack detection to eliminate the possibility of misjudgement and the latter uses a self-destruction defence measure against node capture attack, without actually destroying the node's radio service, to avoid a major security breach.

For certain security‐sensitive wireless sensor network (WSN) applications, physical location information of the sensor nodes must not be disclosed to any unauthorised entity. During the localisation phase for such applications the physical locations of sensor nodes are kept secret. Globally, a number of secure location estimation schemes have been proposed from various perspectives, but some important constraints of sensor nodes are often ignored. The considered limitations during design of those schemes vary with respect to varying research perspective. In this study, we propose a novel security framework for secure location estimation of sensor nodes suitable for security‐sensitive WSN applications. The proposed framework aims to provide security, scalability, adaptability and optimise power consumption during the secure location estimation phase of a wireless sensor network. The designed framework consists of a two‐way authentication scheme, a light‐weight encryption mechanism and a novel secure key generation algorithm. The study discusses strengths of the components if used for secure localisation individually, as well as when used together as interactive parts of a security framework for WSN applications.

Underwater wireless sensor networks often employ acoustic channels for communications because radio signals do not work well in water. UWSNs usually have very dynamic topology as sensors moves passively with water current. Some routing protocols have been proposed to the challenging problem in UWSNs. In UWSNs, efficient utilization of energy is one of the major issues. In DBR, routing is based on the depth of the sensor nodes. The nodes having less depth are used as a forward node and consume more energy as compare to the rest of the nodes. In this paper, we propose a light-weight depth-based routing protocol (LDBR). In LDBR, residual energy based approach is used to minimize the energy consumption. Extensive simulations have been designed and conducted to evaluate the proposed method. The results show that the LDBR consumes less energy as compare to its predecessor DBR.

Routing sensor data from sensor node to base station is a challenging task in a wireless sensor network (WSN) application. The sensor nodes have a number of constraints such as limited energy, low memory, processing capabilities, etc. It is important to consider these constraints while designing a routing protocol so that the overall network lifetime and the data robustness may be efficiently maintained. This research focuses on improving the Two-Level Hierarchy for Low Energy Adaptive Clustering Hierarchy (TL-LEACH) protocol to provide energy efficiency; in terms of communication overhead and making the communication among the end-nodes, cluster-heads and base station as robust as possible. Two major drawbacks of the TL-LEACH protocol have been focused in this research that are mainly related to using the protocol for large-scale WSN and making the communication among the nodes robust. A novel cluster-head selection mechanism has been introduced to improve the energy-efficiency of the TL-LEACH and the new version has been named as Extended TL-LEACH (ETL-LEACH). The simulation results show that the ETL-LEACH performs better in terms of energy consumption, node lifetime and the communication delay has been decreased to a significant amount.

In this paper, we propose a novel trust computation framework (TCF) for cloud services. Trust is computed by taking into consideration multi-dimensional quality of service (QoS) evidence and user feedback. Feedback provides ample evidence regarding the quality of experience (QoE) of cloud service users. However, in some cases, users may behave maliciously and report false feedback. Users can carry out collusion and Sybil attacks to slander/self-promote cloud services. Trust computed in such cases could be misleading and inaccurate. Evaluating the credibility of user feedback can help in not only preventing the collusion and Sybil attacks but also remunerating the affected cloud services. Despite the advantages of credibility evaluation, very few studies take into consideration feedback credibility and multi-dimensional evaluation criteria. Considering the limitations of existing studies, we propose a new TCF in which trust is computed by aggregating multi-dimensional evidence from QoS and QoE. We have used multi-dimensional QoS attributes to compute the objective trust of cloud services. The QoS attributes are divided into three dimensions, i.e., node profile, average resource consumption, and performance. The node profile of a cloud service is attributed to CPU frequency, memory size, and hard disk capacity. The average resource consumption is quantified based on the current CPU utilisation rate, current memory utilisation rate, current hard disk utilisation rate, and energy consumption. Moreover, the performance of a cloud service is measured by the average response time and task success ratio. Besides that, the credibility of feedback is evaluated to prevent the malicious behaviour of cloud users. Our results demonstrate the effectiveness of our proposed TCF in computing accurate trust in cloud services.

Early warnings with respect to natural disasters, specially floods and drought predictions play a vital role in saving precious lives and assets. Most of the population of Pakistan gets affected by the floods/drought every year. A huge loss associated with the natural disaster includes finance, asset and precious lives. In this paper we present a novel wireless sensor network (WSN) based flood/drought forecasting system (FDFS) for Pakistan to help authorities gain early information regarding flooding/drought possibilities and take timely measures for the relief. The proposed system has been simulated and tested using Network Simulator (NS).